Copper base alloy

ABSTRACT

In essence, this invention relates to a copper base alloy comprising 0.1 - 5 percent by weight of Sn, 0.1 - 5 percent by weight of Zn, 0.1 - 5 percent by weight of Pb and 2.5 - 10 percent by weight of Al, the balance being copper and ordinary impurities. According to this invention, there are provided a high strength copper base alloy excellent in corrosion resistance and machinability, an iron-containing, high strength copper base alloy excellent in corrosion resistance and machinability, an aluminum-containing copper base alloy excellent in corrosion resistance and machinability, and a tough copper base alloy excellent in impact resistance and machinability, by changing the aluminum content in said basic alloy, adding Fe in an amount ranging from 0.1 to 5 percent by weight to said basic alloy, or adding up to 5 percent by weight of Ni, up to 3 percent by weight of Mn and up to 0.1 percent by weight of Be to said basic alloy.

United States Patent Kitazawa et al. 1 1 Dec. 2, 1975 15 1 COPPER BASE ALLOY 3,703,367 11/1972 Cocks 75 159 [75] Inventors: Kunio Kitazawa, Takada; Tatsuichi FOREIGN PATENTS 0 APPLICATIONS Fukusako, Tokyo both of Japan 179,631 7/1949 Japan 75/l56.5 I73] Assignee: Toyo Valve Co., Ltd., Tokyo, Japan [22] Filed: Sept. 4, 1974 Primary Examiner-C Lovell Attorney, Agent, or F1rm-Toren, McGeady and [21] Appl. No.: 503,086 Stanger Related U.S. Application Data [631 Continuation of Ser. No. 277,750, Aug. 3, 1972, [57] ABSTRACT ubundmed- In essence, this invention relates to a copper base alloy comprising 0.1 5 percent by weight of Sn, 0.1 {30] Forelgn Appllcauon Pnonty Data 5 percent by weight of Zn, 0.1 5 percent by weight Aug. 11, 1971 Japan 46-60274 of Pb and 2.5 10 percent by weight of Al, the bal- Mar. 1. 1972 Japan 47-21375 ance being copper and ordinary impurities. According Mar. 2, 1972 Japan 47-21764 to this invention, there are provided a high strength Mar, 3, 1972 Japan 47-22001 copper base alloy excellent in corrosion resistance and machinability, an iron-containing, high strength cop- [52] U.S. Cl. 75/l56.5; 75/153; 75/162 per base alloy excellent in corrosion resistance and [51] Int. Cl. C22C 9/01; C22C 9/02 machinability, an aluminum-containing copper base [58] Field of Search 75/153, 154, 156.5, 157.5, alloy excellent in corrosion resistance and machinabil- 75/159, 162 ity, and a tough copper base alloy excellent in impact resistance and machinability, by changing the alumi- 1 1 References Cited num content in said basic alloy, adding Fe in an UNITED STATES PATENTS amount ranging from 0.1 to 5 percent by weight to 2,101,087 12/1937 Munson 75/157.5 said basic alloy or adding up to 5 percent by weight of 2,492,786 12/1949 Croft 75/157.5 "P to 3 Percent y Weight f Mn and up to 0.1 per- 2.935,400 5/1960 Zeider 61. al. 75/1575 x Cent y Weight of B6 to Said basic y- 3,252,793 5/1966 Hesse 75/157.5 3,370,944 2/1968 Kawasaki 75/1565 8 Drawmgs COPPER BASE ALLOY This is a continuation of application Ser. No. 277,750, filed Aug. 3, 1972 now abandoned.

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a high strength copper base alloy excellent in corrosion resistance and machinability, which comprises as the main ingredients copper and aluminum, and contained therein, tin, zinc, nickel, manganese, beryllium and iron, and to a process for the manufacture of the same.

Cast products of conventional copper base alloys are generally superior to cast products of other metals and alloys, especially ferrous cast products, in respect of electric conductivity, thermal conductivity, dimagnetic property, freedom from cold brittleness, corrosion resistance, color and luster, abrasion resistance, machinability, etc. Especially, a bronze cast product exhibits high abrasion resistance, high corrosion resistance and excellent machinability, and therefore, this alloy is the most suitable for bearings, bushes, sleeves, pump trunks, blade wheels, injectors, attachments for railway uses, parts for meters, valves and cocks for low and medium pressure uses.

However, such alloys cannot be used as valves and cocks for high pressure uses because their mechanical properties, such as, tensile strength, are not good and they are inferior in proof stress, hardness, heat resistance, etc.

On the other hand, an aluminum bronze which is excellent in corrosion resistance, tensile strength, proof stress and hardness is the toughest alloy among casting copper alloys, but this alloy is defective in that it is difficult to produce a cast product of a complicated configuration therefrom and its machinability is especially bad.

A primary object of this invention is to provide a copper base alloy highly improved in tensile strength, proof stress, impact resistance, hardness, corrosion resistance, machinability, abrasion resistance and heat resistance by alloying aluminum into a conventional bronze.

It has heretofore been considered that in bronzes, aluminum is an impurity and the presence of aluminum damages the soundness of such bronze. In particular, the tensile strength of about 23 Kg/mm observed with the addition of 0.005 percent by weight of aluminum is reduced to about 18.5 Kg/mm when the aluminum content is increased to 0.1 percent by weight. Further, the elongation of about 25 percent by weight observed with the addition of 0.005 percent of aluminum is reduced to about percent when the aluminum content is increased to 0.1 percent by weight. Moreover, the pressure loss of 0.7 ml/sec observed with the addition of 0.005 percent by weight of aluminum is increased to 21 ml/sec when the aluminum content is increased to 0.1 percent by weight.

With increase of the aluminum content, these properties are degraded, and the pressure tightness severely deteriorates. Therefore, in practice, the aluminum content is reduced to below 0.005 percent by weight in such alloys.

In this invention, the above-mentioned defects of conventional copper base alloys are overcome by using to 8 percent by weight of aluminum.

Further, an aluminum-containing copper base alloy improved especially in tensile strength is provided by addition of aluminum in an amount of 8 to 10 percent by weight.

Still further, as a result of various tests made on copper base alloys comprising aluminum in an amount varying from 5 to 8 percent by weight, it has been found that there can be provided a copper base alloy having a very high impact resistance by containing 1 to 5 percent by weight of aluminum.

A secondary object of this invention is to provide a corrosion-resistant copper base alloy having excellent color and luster.

The alloy of this invention, when cast, exhibits a beautiful casting skin composed of a tough oxide film of a copper-brown color which is due to the presence of aluminum, and when subjected to the post-treatment, the color of the oxide film is changed into a dark red color or other various colors.

Further, the alloy of this invention is characterized in that the cut surface is highly resistant against atmospheric corrosion as compared with brass, bronze, cupro-nickel and cupro-aluminum.

A third object of this invention is to provide a copper base alloy which is readily ductile by hot working, warm working and cold working. Namely, this invention provides a copper base alloy excellent in not only ductility but also castability.

A fourth object of this invention is to provide a copper base alloy which is highly improved in tensile strength and hardness by containing 2 to 5 percent by weight of Fe.

Other objects and advantages of this inventionwill be apparent from the description given hereinbelow.

Reasons for limitations of contents of ingredients given in this invention will now be explained.

0.1 T0 5 PERCENT BY WEIGHT OF Sn One of characteristic features of the alloy of this invention resides in the Sn content. At Sn contents below 0.1 percent, the. elongation is high, but the proof stress is low. When the Sn content exceeds 2 percent by weight, especially 5 percent by weight, the reduction of elongation is extreme and the resulting alloy is hard and brittle. On the other hand, tin exhibits effects of improving the corrosion resistance and preventing dezincification and dealuminification. Thus, tin is added in an amount ranging from 0.1 to 5 percent by weight. It is especially preferred that the Sn content is adjusted to 0.1 1 percent by weight when high tensile strength, high elongation and high impact resistance are desired and that the Sn content is adjusted to 1 5 percent by weight when high hardness is required.

0.1 T0 5 PERCENT BY WEIGHT OF Zn Mechanical properties, castability, machinability and other processing properties can be improved by addition of a suitable amount of zinc. However, when zinc is contained in an amount not exceeding 0.1 percent by weight, castability is insufficient, and when zinc is contained in too great an amount, the corrosion resistance is reduced and dezincification tends to occur. Therefore, it is desired that the zinc content is controlled to up to 5 percent by weight, especially within a range of from 0.1 to 2.5 percent by weight. Further it is preferred that the Zn content is adjusted to 0.1 1.5 percent by weight when high tensile strength, high elongation are desired, and that the Zn content is adjusted to 1.5 4 percent by weight when high hardness is demanded.

0.1 T PERCENT BY WEIGHT OF Pb When Pb is contained in suitable amounts, lead improves the-machinability and pressure tightness. At Pb Contents below 0.1 percent by weight, sufficient machinability and pressure tightness cannot be obtained, and at Pb contents exceeding 5 percent by weight, reduction of tensile strength, elongation and impact resistance is observed. When the alloy is used as a ductile metal, it is preferred that the Pb content is within a range of from 0.1 to 2 percent by weight.

2.5 T0 5 PERCENT BY WEIGHT, 5 TO 8 PERCENT BY WEIGHT AND 8 TO 10 PERCENT BY WEIGHT OF Al strength, impact resistance, proof stress and hardness are especially desired, aluminum contents exceeding 8 percent by weight exhibit greater improvements than with aluminum contents 5 8 percent. If aluminum is present in an amount exceeding 10 percent by weight, the improving effects are not as significant.

UP TO 5 PERCENT BY WEIGHT OF NI Nickel improves mechanical properties. More specifically, in case nickel is contained in an amount of up to 5 percent by weight the tensile strength is heightened and at the same time, elongation, toughness and corrosion resistance are improved. When nickel is contained in an amount exceeding 5 percent by weight, increase of these effects is not so great and the cost of the alloy is made high. Thus, it is preferred that nickel is contained in an amount of up to 5 percent by weight. In case room temperature rolling is conducted, it is preferred that nickel is contained in an amount of up to 3 percent by weight.

UP TO 3 PERCENT BY WEIGHT OF MN Manganese acts as a deoxidant and gives a cast product of a minute and elaborate structure. When Mn is contained in an amount of 3 percent by weight, tensile strength, impact resistance and abrasion resistance are heightened. At Mn contents exceeding 3 percent by weight, however, no improvement of the toughness is observed and the dross is readily formed during casting step. Therefore, it is preferred that the Mn content is adjusted to up to 3 percent by weight.

0.1 T0 5 PERCENT BY WEIGHT OF FE Iron exhibits the effect of improving castability and grain refining, but at Fe contents below 0.1 percent by weight, these improving effects are very low. In case iron is contained in an amount greater than 2 percent by weight, especially the tensile strength and hardness are highly improved as compared with the case where iron is contained in an amount of up to 2 percent by weight. At Fe contents exceeding 5 percent by weight, reduction of the tensile strength and ductility is ob- 4 served, and hard spots are sometimes formed as a result of the combination of Fe with Al or Sn, thus causing an undesired reduction of machinability. Furthermore, Fe contents 2.5 5 percent are preferable to improve effects of refining grains.

UP T0 0.1 BY WEIGHT OF BE Beryllium is an effective deoxidant and is included for stabilizing each ingredient of the alloy and making the structure of the alloy homogeneous. Further, the amount of aluminum oxide is reduced by addition of Be, and as a result, the fluidity property of the alloy in the molten state is improved. However, too high a Be content is economically disadvantageous because the increase in such improvements is not as great. Thus, it is preferred that beryllium is added in an amount of up to 0.1 percent by weight.

The alloy of this invention can be attained by combining copper with the above-mentioned elements suitably within the above ranges, and as a result, there can be obtained an alloy possessions excellent tensile strength, impact resistance, hardness, corrosion resistance, inachinability, abrasion resistance and heat re sistance.

Another important feature of this invention resides in a process for the production of such alloy. More specifically, this invention provides a process for the production of copper base, alloys comprising adding the abovementioned ingredient elements and melting them to form a molten metal composition comprising the ingredients within the above-mentioned ranges, blowing an inert gas such as N gas and Ar gas into the molten metal and thus effecting the degassing treatment and the alloy grain-refining treatment. During this process, readily oxidizing metals such as Al, Zn and Mn are prevented from being converted into oxides by the selective oxidation of Be, and the formation of such oxides are inhibited and stabilization of the ingredients can be accomplished.

The conditions for the degassing treatment should be selected so that removal of dissolved hydrogen gas, floating and removal of suspended oxides, and dispersion and refining of alloy grains can be sufficiently accomplished. In view of the foregoing, the temperature of the molten metal, the treatment time, the blowing method and other conditions are suitably chosen. This treatment may be conducted once or repeated several times during the melting step.

As impurities that may be contained in the alloy of this invention, there may be mentioned phosphorus,

' sulfur, chromium, magnesium, etc. The alloy of this invention may further comprise silicon, silver, arsenic, indium, etc. as minor alloying elements which do not alter the characteristics of the alloy. However, in the alloy of this invention, the total content of these impurities and minor alloying elements is maintained at a level not exceeding 1 percent by weight.

Uses of the alloy of this invention are summarized below.

1. Articles, machines and parts, of which pressure tightness, abrasion resistance, corrosion resistance, erosion resistance, mechanical strength and machinability are required, and those, of which strength, corrosion resistance, erosion resistance, acid resistance and abrasion resistance are required, such as bearings (for bridge parts, machine tools, electrical instruments, pump propeller shafts, ships, transportation facilities. etc.), pump bodies, bushes, sleeves, blade wheels,

valves (high temperature valves, high pressure valves, heat-resistant valves, low temperature valves, erosionresistant valves, sea water-resistant valves, acid-resistant valves, water steam-resistant valves and moistureresistant valves), valve parts (bodies, bonnets, stems, discs, body rings and sheets rings), cocks, railway parts, ship parts, flanges, liners, pistons, machine parts, engine parts, carburetor, oil rings, meter parts, joints, parts for the ocean development, parts of machines for preventing public pollution, parts of water-supply facilities, draining facilities and sanitary equipments, parts of freezers and air-conditioning machines, vessels for high pressure gas, parts for atomic power plants, condensing tubes for heat exchangers, water cooling parts of heat exchangers, automobile parts, gears, valve seats, worm gears, machine parts for the chemical industries where acid resistance and sea water resistance are required, bearing cages and friction parts of thrusts, etc.

2. Articles, machines and parts, of which castability, processability, machinability and resistance against atmospheric corrosion are required, such as general tools, construction tools, parts of water-supply facilities, draining facilities and sanitary equipments, decoration parts, name plates, and parts of machines for preventing public pollution, etc.

3. Ductile metal such as rods, plates, pipes and ordinary decoration materials, etc.

4. Materials for forging (including the melt forging).

Functions and effects of the alloy of this invention will now be explained more specifically by reference to examples.

Alloys shown in examples are prepared, for instance, by the following method. After a melting furnace and a melting vessel have been heated sufficiently, preheated return scrap and ingot of copper are charged. After the charge has been made completely molten, zinc (brass scrap), copper-tin alloy ingot and lead ingot are added to the melt. The heating is continued to attain the melt temperature of 1,250C. Then, nickel ingot (nickelcopper alloy ingot), manganese ingot (manganese-copper alloy), aluminum ingot (alluminum-copper alloy) and berylliumcopper alloy ingot are added to the melt, and the melt is stirred gently. Immediately, dried inert gas is blown into the melt for 3 10 minutes to such an extent that the surface of the melt is not so disturbed, thereby to effect the degassing treatment. This treatment is carried out as deliberately and sufficiently as possible. Immediately after completion of the degassing treatment, the molten metal is cast into the chill block test piece for quality control, and the spontaneously solidified surface and the fracture surface are examined. When the draw is observed in the spontaneously solidified surface and the fracture surface has a minute and fine structure, the melt is regarded as having good quality and is cast into a prepared mold.

Nextly, examples are shown, but example 1 example 9 are corresponding to the following copper base alloy (1) (5), especially (6) (7) (8).

1. A high strength copper base alloy excellent in corrosion resistance and machinability, which comprises 0.1 5 percent by weight of Sn, 0.1 5 percent by weight of Zn, 0.1 5 percent by weight of Pb and 2.5 10 percent by weight of Al, the balance being Cu and ordinary impurities.

2. A high strength, iron-containing, copper base alloy excellent in corrosion resistance and machinability, which comprises 0.1 5 percent by weight of Sn, 0.1

6 5 percent by weight of Zn, 0.1 5 percent by weight of Pb, 2.5 10 percent by weight of Al and 0.1 5 percent by weight of Fe, the balance being Cu and ordinary impurities.

3. An alloy set forth in (1), which further comprises at least one of Ni in an amount of up to 5 percent by weight, Mn in an amount of up to 3 percent by weight and Be in an amount of by weight, with or without addition of 0.1 5 percent by weight of Fe.

4. A high strength copper base alloy excellent in corrosion resistance and machinability, which comprises 0.1 5 percent by weight of Sn, 0.1 5 percent by weight of Zn, 0.1 5 percent by weight of Pb and 3 10 percent by weight of Al, the balance being Cu and ordinary impurities.

5. An alloy set forth in (4), which further comprises at least one of Fe in an amount of 0.1 5 percent by weight, Ni in an amount of up to 5 percent by weight, Mn in an amount of up to 3 percent by weight and Be in an amount of up to 0.1 percent by weight.

6. A high strength copper base alloy excellent in corrosion resistance and machinability, which comprises 0.1 4 percent weight of Sn, 0.1 4 percent by weight of Zn, 0.1 4 4 percent by weight of Pb and 5 8 percent by weight of Al, the balance being Cu and ordinary impurities.

7. A high strength, iron-containing, copper base alloy excellent in corrosion resistance and machinability, which comprises 0.1 4 percent by weight of Sn, O.l 4 percent by weight of Zn, 0.1 4 percent by weight of Pb, 5 8 percent by weight of Al and 0.1 5 percent by weight of Fe, the balance being Cu and ordinary impurities.

8. An alloy set forth in (6), which further comprises at least one of Ni in an amount of up to 5 percent by weight, Mn in an amount of up to 3 percent by weight and Be in an amount of up to 0.1 percent by weight, with or without addition of 0.1 5 percent by weight of Fe.

EXAMPLE 1 Table 1 illustrates data of the chemical composition, tensile strength, elongation and hardness of examples of the alloy of this invention.

In each sample, the casting was effected at l,150 1,200C. and JIS (Japanese Industrial Standard) A test specimens (Y block) were formed (in the case of samples Nos. 18 2O JIS B test specimens were formed), JIS No. 4 tension test pieces were processed from such cast specimens and their properties were examined.

In samples Nos. 1, 2, 3, 4 and 5, the influence by change in the Sn content was examined. In sample No.1 the Sn content is lower (almost trace) than in the alloy of this invention. Samples Nos. 2, 3 and 4 are those of alloys according to Example 1. In sample No.5, the Pb content is higher than in the alloy of Example 1.

The Sn content (percent by weight) is one of great factors determining the tensile strength and elongation in the alloy of this invention.

In samples Nos. 6, 7 and 8 the change in the Zn content was examined, and in samples Nos. 9, l0 and 11 the change in the Pb content was examined.

In each of the above samples, a great difference of the tensile strength is not observed, but it is seen that when either the Zn content or the Pb content is outside the range specified in Example 1, the elongation is reduced.

Table 1 Mechanical Properties Sample Chemical Composition (/1 by weight) Tensile Elon- Remarks No. Cu Sn Zn Pb Al Ni Mn Fe impu strength gation Hardness rities (Kg/mm (70) 1 88.0 2.0 4.0 5.6 0 0 0 0.40 28.3 44 90 Comparison 2 88.0 0.1 2.0 4.0 5.6 0 0 0 0.30 29.5 40 90 Example 3 87.0 1.5 2.0 3.9 5.5 0 0 0 0.10 29.5 20 110 Example 4 86.1 2.0 1.6 3.9 6.2 0 0 0 0.20 31.0 12 104 Example 5 81.7 3.9 4.0 4.4 5.5 O 0 0 0.50 29.5 4 121 Comparison 6 86.8 2.1 0.1 4.4 6.3 0 0 0 0.10 31.3 13 110 Comparison 7 86.6 1.7 2.0 3.5 6.0 0 0 0 0.20 33.2 21 Example 8 82.1 2.0 4.1 4.2 7.3 0 0 O 0.30 30.0 8 114 Comparison 85.8 22 4.3 1.6 6.1 0 0 0 0.30 30.5 8 110 Comparison 10 86.5 1.7 2.0 3.5 6.1 0 0 0 0.20 36.5 23 110 Example 11 85.5 1.7 1.6 4.2 6.9 0 0 0 0.10 31.0 14 110 Comparison 12 83.3 3.9 4.5 4.8 2.6 0 0 0 0.90 15.3 3 Comparison 13 85.9 1.8 1.8 3.8 6.4 0 0 0 0.30 34.3 20 114 Example 14 84.2 1.8 1.8 3.6 8.5 0 0 0 0.10 32.5 3 I38 Comparison 15 84.9 1.7 1.5 3.9 6.6 1.3 0 0 0.10 31.3 26 104 Example 16 85.3 1.5 1.9 3.9 6.3 O 0.9 0 0.20 31.8 24 104 Example 17 82.0 1.6 1.6 3.5 7.9 2.4 0.8 0 0.20 34.0 26 110 Example 18 86.0 1.7 1.7 3.7 6.4 0 0 0 0.50 33.8 18 125 Example 19 85.1 1.7 1.7 3.6 6.0 0.7 0.8 0.3 0.10 41.6 30 117 Example 20 83.8 1.6 1.6 3.5 6.5 1.5 0.9 0.5 0.10 38.3 110 Example In samples Nos. 12, 13 and 14 the influence by change in the aluminum content was examined. In sample No.12, the aluminum content is lower than the range specified in Example 1 (the Zn and Pb contents are higher); therefore, the tensile strength and elongation are low. In sample No.14, the tensile strength is high, but the elongation is low. The aluminum content (percent by weight) is one of the important factors determining the tensile strength and elongation of the alloy of this invention.

Effects attained by addition of Ni and Mn were examined in samples Nos. 15, 16 and 17. In each sample,

. high tensile strength and high elongation are obtained.

Especially with respect to the elongation, good results are obtained constantly.

Results of samples Nos. 18, 19 and 20 are those of JIS-B test specimens. From these results, it is seen that in JIS-B test specimens higher tensile strength and higher elongation can be more consistently obtained than in JIS-A test specimens.

EXAMPLE 2A JIS A test specimens were cast at about 1,150C. from alloys according to Example 2 and alloys according to JIS BC 6, and JIS No.4 tension test pieces were prepared therefrom. Mechanical properties of these pieces are shown in Table 2.

From the results, it is seen that alloys of Example 2 have higher tensile strength and higher hardness than comparative alloys. More specifically, the tensile strength of the alloys of this invention is higher by about 30 percent than that of the comparative alloys and the hardness of the alloys of this invention is higher by about 40 percent than that of the comparative alloys. Further, the proof stress of the alloys of this invention is higher by about 75 percent than that of the Table 3 shows results of Charpy impact tests made on JIS No.3 impact test pieces with U-notches from the alloy of Example 2 and the alloy according to JIS BC 6.

As compared with the alloy corresponding to JIS BC 6 in which the impact value is greatly lowered at temperatures exceeding 200C, the alloy of Example 2 is excellent in that a reduction in the impact value is not observed at temperatures of up to 300C. At temperatures exceeding 200C., the impact value of the alloy of Example 2 is higher by about percent than that of the alloy according to JIS BC 6, and at 300C. the impact value of the alloy of this invention is higher by about 150 percent than that of the JIS BC 6 alloy. Thus, it is seen that the alloy of this invention exhibits high and stable mechanical properties at high temperatures.

EXAMPLE 3 Table 2 Chemical Composition (71 by weight) Mechanical Properties Sample Tensile Elon- Hard-' Proof Cu Sn Zn Pb Al Ni Mn Fe impustrength gallon ncss Stress rities (Kg/mm (/z) (HB) (Kglmm Alloys of 86.5 1.7 2.0 3.5 6.1 0 0 0 0.20 36.5 23 110 21.1 Example 2 82.0 1.6 1.6 3.5 7 9 2.4 0.8 0 0.20 34.0 26 110 20.9 Alloys 84.3 4.4 5.2 5.6 0.4 0 0.10 26.5 "8 74 12.2 according to JIS 84.0 4.7 5.1 5.7 0 0 0.50 25.8 22 75 11.5

Table 4 Chemical Composition (7! by weight) Relative value of Machina- Cu Sn Zn Pb Ni A1 Others bility leaded 85 5 5 5 90 bronze 81 3 9 7 90 81 3 15 6 9O leaded 70 5 25 90 1st bronze 80 l0 10 80 group 78 7 80 brass 71 l 25 3 80 67 l 29 3 80 free cutting 61.5 35.5 3 100 brass rod tin 88 6 4 2 60 2nd bronze 88 10 2 50 group 88 8 4 50 brass 61 0.75 35.5 0.75 60 high 3rd strength 64 balance 7.5 3(Fe) group brass aluminum 89 10 [(Fe) 35 bronze 85 11 4(Fe) 20 4th alloy of group Example 3 85.5 1.5 1.5 3.5 1 7 90 Table 4 illustrates relative values of machinability of casting and ductile metal of various copper alloys, each relative value being calculated based on the value of free-cutting brass rod as 100.

Higher contents of lead give a better machinability, and aluminum bronze and high strength brass, each of which contains aluminum are inferior in machinability. In contrast, even if the alloy of Example 3 contains aluminum, since it also contains lead, it exhibits an excellent machinability comparable to that of the HS BC 6 alloy.

*dczincificalinn was observed The chemical composition of the alloy according to Example 4 is following:

Cu 85.9%, Sn 1.8%, Pb 3.8%, A1 6.4%, impurities The alloy of Example 4 and the 11S BC 6 alloy were cast into 118 B test specimens, and test specimens having a size of 35 mm X 20 mm X 3 mm were prepared therefrom. These test specimens were dipped in a corrosive liquid to examine the weight decrease by corrosion.

The pH of the corrosive liquid was adjusted as indicated in Table 5, and the test was carried out at room temperature. The value of the weight decrease by corrosion is converted to the value of the unit of mglcm lmonth. Results are shown in Table 5.

The alloy of Example 4 exhibits a low weight decrease especially at either low or high pH values (good resistance especially against contaminated water or contaminated sea water), and has a very good corrosion resistance.

EXAMPLE 5 Table 6 illustrates data of the chemical composition, tensile strength, elongation and hardness of examples of the alloy of this-invention.

In each case, JlS-B specimens were cast at 1,150C. 1,200C. and .115 No. 4 tension test pieces were prepared from them to determine the properties.

In samples Nos. 1, 2, 3 and 4, the influence by change in the Sn content was examined. Sample No. 1 has the Sn content lower than the range specified in this inven- 30% tion, the Sn content of each of samples Nos. 2 and 3 is within the range specified in Example 5, and the Sn content of sample N0. 4 is above the upper limit of the preferable Sn content specified in Example 5.

Table 6 Mechanical Sample Chemical Composition (7: by weight) Properties Tensile Elon- Remarks No. Cu Sn Zn Pb Al Ni Mn Fe impustrength gation Hardness rities (Kg/mm) 1 88.0 0 2.0 4.0 5.6 0 O 0 0.40 28.3 44 Comparison 2 85.4 0.1 2.2 3.5 6.3 0 O 2.3 0.20 35.5 20 Example 3 84.2 2.0 1.8 3.1 5.8 0 0 2.8 0.30 37.6 10 120 4 82.1 4.5 1.5 3.7 5.5 0 0 2.3 0.40 35.4 4 Comparison 5 85.3 2.0 0.1 3.6 6.1 0 0 2.5 0.40 33.7 20 Example 6 82.1 1.8 2.5 3.8 6.8 0 0 2.6 0.40 33.0 18 120, 7 81.6 2.2 4.3 3.2 5.9 0 0 2.6 0.20 30.2 8 113 Comparison 8 85.0 1.6 2.0 1.2 7.0 0 O 2.9 0.30 41.3 14 128 Example 9 83.3 2.0 1.8 3.4 6.5 0 0 2.7 0.30 39.3 20 107 10 83.0 1.8 1.8 4.3 6.6 0 0 2.1 0.40 30.4 15 110 Comparison Table 6 Cntinued Mechanical Sample Chemical Composition (/2 by weight) Properties Tensile Elon- Remarks No. Cu Sn Zn Pb Al Ni Mn Fe impustrength gation Hardness rities (Kg/mm (/c) (HB) 11 86.5 1.5 1.9 3.9 3.1 0 0 2.8 0.30 20.2 3 12 81.7 3.1 2.2 3.6 6.5 0 0 2.5 0.40 38.5 18 115 Example 13 80.9 1.8 2.0 3.9 8.7 0 0 2.5 0.20 44.8 130 Comparison 14 86.5 1.7 2.0 3.5 6.1 0 0 0 0.20 36.5 23 110 Example 15 84.9 1.6 1.5 3.7 6.0 0.01 0 1.7 0.30 32.0 31 93.6

16 83.5 1.6 0.9 3.7 6.6 0.02 0 3.5 0.20 45.7 15 130 Example 17 82.7 1.5 1.4 3.5 6.1 0 O 4.6 0.20 45.2 12 135 18 81.6 1.6 1.5 3.7 6.0 0 0 5.3 0.30 50.9 5 135 Comparison 19 85.1 1.7 1.7 3.6 6.0 0.7 0.8 0.3 0.10 41.6 30 117 Example 20 81.9 1.7 1.5 3.3 6.5 0.9 1.0 3.1 0.10 52.5 21 140 The Sn content (percent by weight) is one of great factors determining the tensile strength and elongation of the alloy of this invention.

In samples Nos. 5, 6 and 7, the influence by change in the Zn content was examined. Samples Nos. 5 and 6 are samples of the allow of Example 5, and the Zn content of Sample No.7 is above the upper limit specified in Example 5. Samples Nos. 8, 9 and 10 were given to examine the influence by change'in the Pb content. Samples Nos. 8 and 9 are of the alloy of Example 5, and the Pb weight. Samples Nos. 10 and 20 were given to examine effects attained by addition of Ni and Mn. From the data it is seen that good results are consistently obtained with respect to the tensile strength by addition of these elements.

M 6 content of Sample No. 10 is above the upper l1m1t spec- EXA PLE Table 7 Chemical Composition by weight) Alloy Cu Sn Zn Pb A1 Fe Ni Mn impurities Alloys of 85.3 1.7 2.1 3.2 7.4 3.3 0 0 0.3 Example 6-1 83.6 1.5 1.8 3.0 7.2 2.6 0 O 0.3 'Alloys of 85.1 1.8 2.0 3.2 7.4 O 0 0 0.5 Example 6-2 86.5 1.8 1.5 3.0 6.5 0.3 0 0 0.4 Alloys 83.4 4.5 6.0 5.6 0.3 O 0.2 corresponding 83.4 4.3 6.5 5.5 0 0 0.3 to .115 BC 6 Mechanical Properties Alloy Tensile Elon- Proof Hardness strength gation stress (HB) (Kg/m (Kg/mm) Alloys of 42.2 20 22.8 135 Example 6-1 41.6 22 21.0 130 Alloys of 36.4 23 20.5 110 Example 6-2 34.0 25 19.7 110 Alloys 27.5 27 12.5 75 corresponding 28.3 25 12.0 73 to .115 BC 6 ified in Example 5. In each of these samples, a substantial difference of the tensile strength is not observed, but from the data of these samples, it is seen that the elongation is reduced if either the Zn or Pb content is outside the range specified in Example 5. Samples Nos. 11, 12 and 13 were given to examine the influence by change in the A1 content. In Sample No. l 1, the A1 content is below the lower limit specified in Example 5, the A1 content of Sample No.12 is within the range specified in Example 5, and the Al content of Sample No. 13 is above the upper limit specified in one embodiment of Example 5. The aluminum content (percent by weight) is one of great factors determining the tensile strength and elongation of the alloy of this invention.

Samples Nos. 14, 15. 16, 17 and 18 were given to examine the influence by change in the Fe content. Samples Nos. 14. 15, 16 and 17 are of the alloy of Example JlS-B test specimens were cast at about 1,150C. from the alloy of Example 6-1, the alloy of Example 62 and the .1 18 BC 6 alloy, and HS No.4 tension test pieces wereprocessed therefrom. Results of determination of properties of these pieces are shown in Table 7.

From the results it is seen that the alloy of Example 6-1 is superior to the alloy of Example 6-2 and the .118 BC 6 alloy with respect to the tensile strength and hardness. More specifically, the tensile strength of the alloy of Example 6-1 is higher by about 19 percent and by about 50 percent than those of the alloy of Example 6-2 and the J 18 BC 6 alloy, respectively. Further, the hardness of the alloy of Example 6-1 is higher than by about 20 percent and by about 79 percent than those of the alloy of Example 6-2 and the .118 BC 6 alloy, respectively.

EXAMPLE 7 sample of a certain thickness under a load of about Table 8 Impact Value (Kg-m/cm Alloy Temperature 75C. C. 100C. 200C. 300C.

alloy of 2.6-3.0 2.7-3.2 3.0-3.2 3.0-3.2 2.6-3.0 Example 7-2 2.5-3.0 2.8-3.5 3.0-3.5 3.1 -3.5 2.8-3.2 JIS BC 6 2.2-2.6 2.5-2.8 2.5-2.8 2.1 -2.3 l.0-l.5 alloy Table 9 Chemical Composition (7c by weight) Alloy Cu Sn Zn Pb Al Fe Ni Mn impurities alloy of 83.5 1.3 2.0 3.1 6.9 2.8 O 0 0.40 Example 7-1 alloy of 85.04 1.6 2.2 3.3 7.5 0.06 0 0 030 Example 7-2 115 BC 6 83.73 4.5 6.1 5.2 0.1 0.32 0 0105 alloy Table 8 illustrates results of the Charpy impact test at different temperatures made on U-notched test pieces prepared from alloys of Example 7-l, 7-2 and the HS BV 6 alloy.

Table 9 illustrates the data of chemical compositions of these samples.

In contract to the .115 BC 6 alloy in which the impact value is greatly decreased at temperatures exceeding 200C, either the alloy of Example 7-1 or the alloy of Example 7-2 does not show the reduction of the impact value at temperatures up to 300C. The impact value of EXAMPLE 9 the alloy of Example 7-1 15 higher by about 39 percent at 200C. and by about 100 percent at 300C. than the Table l l impact value of the .118 BC 6 alloy. The alloy of Examweight Decrease by Corrosion ple 7-1 exhibits an impact value equivalent to that of (mg/cmlmonth) the alloy of Example 7-2 at each temperature stage. Casting alloy alloy of according to Alloy of EXAMPLE 8 pH value Example 9-1 .118 BC 6 Example 9-2 Table 10 Chemical Composition by weight) Relative value of Alloy Cu Sn Zn Pb Ni Al Others Machinability alloy of 83.7 1.6 1.5 3.7 0 6 3.5(Fe) Example 8-1 alloy of 85.3 1.5 1.5 3.5 1 7 0.2 Example 8-2 (impurities) .us 8C6 83.7 4.3 6.0 5.5 0.3 0.2 90 alloy (impurities) 11s AlBC 1 86.3 0.3 9.1 3.2(Fe) 22 alloy freecutting 59.5 0.2 balance 3 0.2(Fe) brass rod Table 10 illustrates the relative values of machinabil- 2 11.43 15.07 8.19 ity of casting and ductile metal of various copper alloys, 2 8 3?: 8 :2 each relative value being calculated based on the value 9 of a free-cutting brass rod as 100. 11 8.92 14.12 8.49 The machinability was compared with respect to a 6O 12 reciprocal number of the time required for boring a Table 12 Chemical Composition (/1 by weight) Alloy Cu Sn Zn Pb Al Ni Mn Fe impurities Alloy of 83.6 1.7 3.4 6.4 0 0 3.1 0.3 Example 9-1 115 BC 6 83.7 4.3 6.0 5.5 0.3 0 0.2

alloy Table l2-continued Chemical Composition (7! by weight) Alloy Cu Sn Zn Pb Al Ni Mn Fe impurities Alloy of 85.5 1.5 2.1 3.5 7.2 0 0.2 Example 9-2 The alloy of Example 9- 1, the .115 BC 6 alloy and the 9. At high strength copper base alloy excellent in coralloy of Example 9-2 were cast to form J1S B test specirosion resistance and machinability, which comprises mens, from which test pieces having a size of 35mm X 0.1 4 percent by weight of Sn, 0.1 4 percent by 20 mm X 3 mm were prepared. The test pieces were weight of Zn, 0.1 4 percent by weight of Pb and 8 dipped in a corrosive liquid having a pH value shown in 10 percent by weight of Al, the balance being Cu and Table 11. The corrosion test was conducted at room ordinary impurities. temperature and the weight decrease by corrosion was 10. A high strength copper base alloy excellent in determined and converted to the value of the unit of corrosion resistance and machinability, which commg/cm /month. The results are shown in Table 1 l. prises 0.1 4 percent by weight of Sn, 0.1 4 percent Table 12 illustrates chemical compositions of these by weight of Zn, 0.1 4 percent by weight of Pb, 8 10 mples. percent by weight of Al and 0.1 5 percent by weight As is seen from the results shown in Table 11, the of Fe, the balance being Cu and ordinary impurities. alloy of Example 9-1 exhibits a lower weight decrease 1 1. An alloy set forth in (9), which further compriese by corrosion expecially at lower pH values and higher at least one of Ni in an amount of up to 5 percent by pH values than the .115 BC 6 alloy. Thus, it will readily weight, Mn in an amount of up to 3 percent by weight be understood that the alloy of Example 9-1 is excellent and Be in an amount of up to 0.1 percent by weight, in corrosion resistance. with or without addition of 0.1 5 percent by weight of The following examples l0 14 correspond to the Fe. followin co er base allo s (l) (5), es eciall (9) (10) (1 y p y EXAMPLE 10 l. A high strength copper base alloy excellent in cor- Table 13 illustrates data of the chemical composirosion resistance and machinability, which comprises tion, tensile strength, elongation and hardness of exam- 0.1 5 percent by weight of Sn, 0.1 5 percent by ples of the alloy of this invention. weight of Zn, 0.1 5 percent by weight of Pb and 2.5 Each sample was cast at 1,150- 1,200C. To form a 10 percent by weight of Al, the balance being Cu and HS B test specimen (in sample No. 17, a JIS A test ordinary impurities. specimen was formed), and the specimen was pro- 2. A high strength, iron-containing, copper base alloy cessed into a J [S No. 4 tension test pieces and its propexcellent in corrosion resistance and machinability, erties were determined. which comprises 0.1 5 percent by weight of Sn, 0.1 14 Samples Nos. 1, 2, 3 and 4 were given to examine the 5 percent by weight of Zn, 0.1 5 percent by weight of influence by change in the Sn content. The Sn content Pb, 2.5 10 percent by weight of Al and 0.1 5 percent of sample No. l is lower than the lower limit specified by weight of Fe, the balance being Cu and ordinary imin this invention, the Sn contents of samples Nos. 2, 3, purities. and 4 are within the range specified in Example 10.

3. An alloy set forth in (1), which further comprises The Sn content (percent by weight) is one of great at least one of Ni in an amount of up to 5 percent by factors having influence on the tensile strength and weight, Mn in an amount of up to 3 percent by weight elongation of the alloy of this invention. and Be in an amount of up to 0.1 percent by weight, Samples Nos. 5, 6, 7 and 8 were given to examine the with or without addition of 0.1 5 percent by weight of influence by change in the Zn content. In samples Nos. Fe. 5, 6 and 7 and Zn content is within the range specified 4. A high strength copper base alloy excellent in corin Example 10, but in sample No. 8 the Zn content is rosion resistance and machinability, which comprises above the upper limit specified in this invention. From 0.1 5 percent by weight of Sn, 0.1 5 percent by the results shown in the Table, it is seen that the elongaweight of Zn, 0.1 5 percent by weight of Pb and 3 tion is reduced when the Zn content is outside the 10 percent by weight of Al, the balance being Cu and range specified in this invention. Samples Nos. 9, 1O ordinary impurities. and 1 l were given to examine the influence by change 5. An alloy set forth in (4), which further comprises in the Pb content. In samples Nos. 9 and 10 the Pb conat least one of Fe in an amount of 0.1 5 percent by tent is within the range specified in Example 10, but the weight, Ni in an amount of up to 5 percent by weight, Pb content of sample No. l 1 is outside the range speci- Mn in an amount of up to 3 percent by weight and Be fied in this invention, i.e., higher than in an amount of up to 0.1 percent by weight.

Table 13 Mechanical Chemical Composition (7: by weight) Properties Tensile Elon- I 5 Sample impustrength gation (HB Remarks No. Cu Sn Zn Pb Al Fe Ni Mn rities (Kg/mm) (9'1) 10/ 1000) 1 89.22 0.05 0.60 0.60 8.89 0.34 0 0 0.30 40.9 42 89.8 Comparison 2 88.95 0.50 0.62 0.10 8.67 0.80 0 0 0.35 44.2 48 Example 3 86.01 1.95 0.70 1.20 8.70 1.03 0 0 0.41 36.7 12 107 4 86.64 2.40 0.54 1.27 7.85 1.10 0 0 0.20 36.1 8 104 5 89.00 0.50 0.10 0.82 8.40 0.93 0 0 0.25 38.0 32 87.2

Table l3-continued Mechanical Chemical Composition (/1 by weight) Properties Sample Tensile Elon- Remarks impu strength gation (HB No. Cu Sn Zn Pb Al Fe Ni Mn rities (Kg/mm") 1%) 10/1000) 8 83.35 0.65 5.10 1.00 8.80 0.80 0 0 0.30 39.6 125 Comparison 9 88.22 0.50 0.81 1.10 8.95 0.20 0 0 0.22 43.9 31 101 Example 10 86.38 0.61 0.78 .70 8.95 0.20 0 0 0.38 43.2 23 104 11 84.58 0.55 0.50 5.30 8.60 0.16 0 0 0.31 32.8 8 101 Comparison 12 88.96 0.68 0.53 1.10 8.50 0.03 0 0 0.20 44.2 37 97.8 Example 13 87.66 0.50 0.56 1.22 8.80 0.90 0 0 0.36 48.4 28 110 14 86.53 0.50 0.66 1.18 8.55 2.41 0 0 0.17 55.2 27 121 16 83.62 0.50 0.50 1.18 8.65 5.30 0 0 0.25 56.8 23 130 Comparison 17 85.90 1.80 1.80 3.80 6.40 0 0 0 0.30 34.3 114 19 87.92 0.70 0.63 1.30 8.10 1.10 0 0 0.25 42.5 30 113 Example 20 87.60 0.53 0.60 0.94 8.90 1.12 0 0 0.31 49.4 34 117 21 86.42 0.50 0.60 1.03 8.90 2.15 0 0 0.40 52.0 26 121 22 83.40 1.60 1.40 3.60 10.35 0.21 0.01 0 0.20 40.5 15 171 Comparison 23 85.72 1.60 1.20 1.75 6.80 0.23 2.50 0.03 0.17 36.7 30 82.6 24 87.72 0.60 1.05 1.70 8.20 0.11 0.10 0.08 0.44 48.3 35 128 Example 25 86.81 0.60 1.05 1.65 9.30 0.11 0.18 0.08 0.40 55.4 135 the upper limit specified in this invention. From the results shown in Table 13, it is seen that such Pb content brings about degradation of the elongation. Samples Nos. 12, 13, 14, 15 and 16 were given to examine the influence by change in the Fe content. The Fe content in samples Nos. l2, l3, l4 and 15 15 within the preferable Fe content range specified in Example 10, while the Fe content of sample No. 16 is higher than the upper limit of the preferable Fe content range specified in this invention. Samples Nos. l7, 18, 19, 20, 21 and 22 were given to examine the influence by change in the Al content. Samples Nos. 17 and 18 are of the alloy in the range of Examples 1 9, samples Nos. 19, 20 and 21 are of the alloy of Example 10 and sample No. 22 is of an alloy in which the Al content is above the upper limit of the Al content specified in this invention. As is 23 is of the alloy in the range: of Examples 1 9. The samples Nos. 24 and 25 are the alloy of this Example 5 10. From the results shown in Table 13, it is seen that higher tensile strength, higher elongation and higher hardness can be attained stably by addition of Ni and Mn.

EXAMPLE 1 1 were determined to obtain results shown in Table 14. In

the case of the sample of the alloy of Example 1 1-2, the HS A test specimen was formed by casting and it was processed into a JlS No. 4 tension test pieces.

Table 14 Chemical Composition by Weight) Alloy lmpuri- Cu Sn Zn Pb Al Fe Ni Mn ties alloy of 86.53 0.50 0.66 1.18 8.55 2.41 0 0 0.17 Example ll-l 86.81 0.60 1.05 1.65 9.30 0.11 0.18 0.08 0.40 .115 BC 6 84.30 4.40 5.20 5.60 0.40 0 0.10 alloy 84.00 4.70 5.10 5.70 0 0 0.50 alloy of 86.50 1.70 2.00 3.50 6.10 0 0 0 0.2.0 Example 1 1-2 82.00 1.60 1.60 3.50 7.90 0 2.40 0.80 0.20

Tensile test Hardness Proof alloy Tensile Elon- (HB stress strength gation 10/ l 000) (Kg/mm'-) g/ alloy of 55.2 27 121 223 Example 1 l-l 55.4 30 135 23.0 JIS BC 6 26.5 28 74 12.2 alloy 25.8 22 75 11.5 alloy of 36.5 23 21.1 Example 1 1-2 34.0 26 110 20.9

Note: the mark" indicates the trace seen from the data shown in Table 13, samples of this From the results shown in Table 14, it will readily be Example 10 are superior to samples of the alloy of Example l 9 (samples Nos. 17 and 18) with respect to the tensile strength, hardness, impact value and proof stress. Thus, the aluminum content (percent by weight) is one of great factors determining the mechanical properties of the alloy of this invention.

Samples Nos. 23, 24 and 25 were given to examine effects attained by addition of Ni and Mn. Sample No.

understood that the alloy of this Example 1 1-1 is superior to the other alloys with respect to the tensile strength, hardness and proof stress. More specifically, the tensile strength of the alloy of this Example is 65 higher by about 1 11 percent and by about 56 percent than those of the .118 BC 6 alloy and the alloy of Example 1 12, respectively. The hardness of the alloy of this example is higher by about 71 percent and by about 16 19 percent than those of the .llS BC 6 alloy and the alloy of Example 11-1, respectively. Futhermore, the proof stress of the alloy of this Example is higher by about 90% and by about 8% than the HS BC 6 alloy and the alloy of Example 1 1-2, respectively.

20 ture stage. The alloy of Example 12-1 is excellent in high temperature mechanical properties and is stable at high temperatures.

The impact value at 200C. of the alloy of Example 12-1 is higher by about 127 percent and by about 39 percent than those of the .IIS BC 6 alloy and the alloy EXAMP E 12 L of Example 12-2, and is comparable to that of the JIS Table Impact Value (Kg-m/cm") Alloy Temperature 75C. C. 100C. 200C. 300C.

alloy of 4.5-4.8 4.7-5.0 4.8-5.2 4.6-5.0 4.5 -4.8 Example 12-1 JlS BC 6 2.2-2.6 2.5-2.8 2.5-2.8 2.l-2.3 1.0-1.5 alloy alloy of 2.7-3.l 3.0-3.6 3.3-3.6 3.3-3.6 2.8-3.4 Example 12-2 .115 AlBC l 5.l-5.4 5.3-5.6 5.3-5.6 5.2-5.4 4.5-4.9 alloy Table 16 Alloy Chemical Composition by weight) Cu Sn Zn Pb Al Fe Ni Mn alloy of Example 12-1* 87.69 0.81 0.56 1.10 9.05 0.47 0 0 .115 BC 6 alloy 83.92 4.30 6.00 5.50 0.28 0 alloy of Example 12-2** 85.46 1.5 2 l 3.5 7.2 0.04 0 0 HS AlBC 1 alloy 86.60 0.05 9.10 3.23 0.29 0.73

Notes: 7

1) *zimpurities content= 0.32% z impurities content 0.20% 2) the mark means the trace.

Table 15 illustrates results of the Charpy impact test made on U-notched JIS No. 3 impact test pieces of the alloy of this Example 12-1, the JIS BC 6 alloy, the alloy of Example 12-2 and the J 1S AlBC l alloy at different temperatures shown in Table 15. The chemical compositions of these sample alloys are shown in Table 16.

NBC 1 alloy. Further, the impact value at 300C. of the alloy of Example 12-1 is higher than by about 220 percent and by about 41 percent than those of the JIS BC 6 alloy and the alloy of Example 12-2, respectively,

40 and is comparable to that of the 11S AlBC 1 alloy.

In contrast to the .115 BC 6 alloy in which the impact EXAMPLE 13 Table 17 Chemical Composition by weight) Relative Alloy Value of Machina- Cu Sn Zn Pb Al Fe Ni Mn bility .llS BC 6 84.96 4.30 4.95 5.50 0.28 0 445 S BSBME 2 58.50 0.40 37.30 3.45 0 0.23 0.21 325 alloy .118 ABBF 2 84.40 0.03 0 0 10.90 2.60 1.08 0.99 alloy .IlS AlBC 1 86.60 0.05 9.10 3.23 0.29 0.73 alloy alloy of 84.65 1.60 1.50 3.70 7.10 0.13 0.67 0.50 400 Example 13-2* alloy of 86.38 0.61 0.78 2.70 8.95 0.20 0 0 250 Example l3-1** alloy of 87.30 0.50 0.50 1.08 8.20 2.11 0 0 201 Example 13-1*** Notes: 1 *2 impurities content 0.22% "z impurities content 0.38% z impurities content 0.30% 2) the mark indicates the trace.

Table 17 illustrates relative values of machinability of casting and ductile metals of various copper alloys,

65 each value being calculated based on the value of HS AlBC l as 100.

Each value was derived from a reciprocal number of the time required for boring a specimen of a certain 2-1 thickness under a load of about Kg by means of a twist drill of a diameter of 7.0 mm (SKH 9) rotated at l 100 rpm on a bench drilling machine.

As is seen from the results shown in the Table, aluminium-containing alloys such as aluminum bronze casting and special aluminum bronze rod are inferior in machinability. In contrast, although the alloy of Example l3-l contains aluminum, it exhibits an excellent machinability, because it also comprises lead.

EXAMPLE 14 Table 18 Weight Decrease by Corrosion The following Examples l7 correspond to the following copper base alloys (1) (5), especially l2) (l3).

1 A high strength copper base alloy excellent in corrosion resistance and machinability, which comprises 0.1 5% by weight of Sn, 0.1 5 percent by weight of Zn, 0.1 5 percent by weight of Pb and 2.5 10 percent by weight of Al, the balance being Cu and ordinary impurities.

2. A high strength, iron-containing, copper base alloy excellent in corrosion resistance and machinability which comprises 0.1 5 percent by weight of Sn, 0.] 5 percent by weight of Zn, 0.1 5 percent by weight of (mglcm lmonth) Pb, 2.5 10% by weight of Al and 0.1 5 percent by alloy .115 BC 6 alloy 115 AlBC 1 l5 weight of Fe, the balance being Cu and ordinary impuof alloy of alloy rifles Example casting Example casting 14-1 14-2 3. An alloy set forth 1n (1), wh1ch further comprises 10% HC 1002 2H2 1168 no at least one of N1 in an amount of up to 5% by weight, pH of 13 15.72 17.70 16.84 15.72 Mn 1n an amount of up to 3 percent by weight and Be in an amount of up to 0.1 percent by weight, with or without addition of 0.1 5 percent by weight of Fe.

Table 19 Chemical Composition by weight) Alloy Cu Sn Zn Pb Al Fe Ni Mn alloy of 87.82 0.55 0.50 1.08 9.10 0.54 0 0 Example l4-l* alloy 83.92 4.30 6.00 5.50 0.28 according to 115 BC 6 alloy of 85.46 1.50 2.10 3.50 7.20 0.04 0 0 Example l4-2** alloy 86.60 0.05 9.10 3.23 0.29 0.73 according to JIS AlBC l Notes:

l impurities content ()Al'7z impurities content 0.207: 2) the mark indicates the trace.

The alloys of this Example 14-1 and Example 14-2, the .llS BC 6 alloy and the JIS AlBC l alloy were cast to obtain .IIS B test specimens, from which test pieces having a size of 10 mm X 10 mm X 8 mm were prepared. These test pieces were dipped in a corrosive liquid.

As the corrosive liquid were used l0 percent HCl and a liquid whose pH was adjusted to 13. The test was conducted at room temperature while keeping the liquid in the tranquil state. The value of the weight decrease by corrosion was converted to the value of the unit of mg/cm /month. Results of the test are shown in Table 18.

Chemical compositions of sample alloys are shown in Table 19.

The alloy of Example l4-l exhibits a smaller weight decrease in 10 percent HCl and high pH value (especially resistant against contaminated sea water and contaminated water) than the 115 BC 6 alloy, the alloy of Example 142 and the J IS AlBC 1 alloy. Thus, it is seen that the alloy of Example 14-1 has a very excellent corrosion resistance. In view of the fact that the results of the alloy of Example l4-l are superior to those of the alloy of Example l4-2, it is presumed that at a low pH value corrosion test, the alloy of this Example will show a smaller weight decrease by corrosion than any of other sample alloys and it will exhibit an excellent corrosion resistance against a low pH liquid.

4. A high strength copper base alloy excellent in corrosion resistance and machinability, which comprises 0.1 5 percent by weight of Sn, 0.1 5 percent by weight of Zn, 0.1 5 percent by weight of Pb and 3 10 percent by weight of Al, the balance being Cu and ordinary impurities.

5. An alloy set forth in (4), which further comprises at least one of Fe in an amount of 0.1 5 percent by weight, Ni in an amount of up to 5 percent by weight, Mn in an amount of up to 3 percent by weight and Be in an amount of up to 0.1 percent by weight.

12. A high strength copper base alloy excellent in impact resistance and machinability, which comprises 0.1 5 percent by weight of Sn, 0.1 5 percent by weight of Zn, 0.1 2 percent by weight of Pb and l 5 percent by weight, preferably 2.5 5 percent by weight, of Al, the balance being Cu and ordinary impurities.

13 An alloy set forth in 12), which further comprises at least one of Fe in an amount of 0.1 4 percent by weight, Ni in an amount of up to 5 percent by weight, Mn in an amount of up to 3 percent by weight and Be in an amount of up to 0.l percent by weight.

EXAMPLE 15 Table 20 illustrates data of the chemical composition, tensile strength, elongation and hardness of examples of the alloy of this invention. In each case, a JlS B test specimen was formed by casting at 1,150"- 1200C. and it was formed into a 118 No. 4 tension test 23 pieces for the tensile test and a 11s No. 3 impact test pieces for the impact test.

'24 influence by change in the Pb content. As the Pb content (percent by weight) increases, each of the tensile Table 20 Chemical Composition by weight) Sample No. Cu Sn Zn Pb Al Ni Mn Fe impurities Mechanical Properties Sample Tensile clonimpact Remarks No. strength gation hardness value (Kglmm (92) (HB) (Kg-m/cm 1 21.8 72 65.6 15.0 Comparison 2 23.7 70 58.2 15.3 Example 3 28.5 49 76.2 11.9

4 30.2 48 80.4 13.0 5 26.6 74.2 8.0 6 26.6 67 65.6 15.6 Comparison 25.5 57 65.6 14.3 Example 7 8 28.6 68 68.6 14.9 9 26.1 65 65.6 13.4 10 18.0 24 54.2 9.8 11 9.2 10 48.6 1.5 Comparison 12 28.1 62 65.6 12.0 13 I 35.4 30 95.0 7.9 Example 14 40.9 27 1 1.0 2.7 Comparison 15 30.5 22 87.2 9.5 Example 16 32.0 18 10.1 7.5 17 34.1 14 11.0 5.2 18 21.4 46 61.0 3.5 Comparison 19 32.6 43 13.4 Example 20 38.3 30 11.0 3.1 Comparison Samples Nos. 1, 2, 3, 4 and 5 were given to examine the influence by change in the Sn content. In sample No. l the Sn content is lower than the lower limit specified in this invention (almost trace), and in samples Nos. 2, 3, 4 and 5, the Sn content is within the range specified in Example 15.

The Sn content (percent by weight) is one of great factors determining the tensile strength and elongation of the alloy of this invention. At the Sn contents below 0.1 percent by weight, although the elongation is high, the proof stress is reduced. At the Sn contents exceeding 5 percent by weight, each of the tensile strength, elongation and impact value is lowered.

Samples Nos. 6, 7 and 8 were given to examine the influence by change in the Zn content. No substantial difference in the tensile strength, elongation or impact value was brought about by the change in the Zn content. However, in view of the castability and corrosion and impact value are reduced.

Samples Nos. 15, 16, 17 and 18 were given to examine the influence by change in the Al content. The increase in the aluminum content (percent by weight) results in heightening of the tensile strength but in lowering of the elongation and impact value. The Al content is one of great factors determining the tensile strength and elongation of the alloy of this invention.

Samples Nos. 19 and 20 were given to examine the effectsattained by addition of Mn and Ni. From the re sults shown in Table 20, it is seen that addition of these elements heightens the tensile strength and elongation stably.

EXAMPLE 16 A Table 23 illustrates the relative values of machinabil- Table 21 Chemical Composition (7( by weight) Alloy Impuri- Cu Sn Zn Pb Al Ni Mn Fe ties 92.5 1.1 2.0 0.4 3.8 0 0 0.20 alloy of 91.2 1.0 2.2 0.7 3.8 0 0 0.8 0.30 Example 16-1 90.4 1.1 2.2 0.5 3.8 09 0.8 0 0.30 alloy of 86.5 1.7 2.0 3.5 6.1 0 0 0 0.20 Example 16-2 82.0 1.6 1.6 3.5 7.9 2.4 0.8 0 0.20

Mechanical Properties Alloy Tensile Elong- Proof strength gation Hardness stress (Kg/mm") (/1) (H13) (Kg/mm") alloy of 26.1 65 65.6 10.3 Example 16-1 30.2 48 80.4 14.1 32.6 43 75.0 17.8

alloy of 36.5 23 11.0 21.1 Example 16-2 34.0 26 11.0 20.9

Table 21 illustrates the mechanical properties of the alloy of Example 161 and the alloy of Example 16-2 for comparison.

From the data shown in the Table, it is seen that the tensile strength of the alloy of Example 16-1 has the value of about 80 percent of the alloy of Example 16-2, the hardness of the alloy of Example 161 has the value of about 70 percent of the alloy of Example 16-2, the proof-stress of the alloy of Example 16-1 has the value of about 75% of the of Example 16-2, but the elongation of the alloy of Example 16-1 has the value of about 200 percent of the alloy of Example 16-2.

EXAMPLE 16 B Table 22 What we claim is:

1. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 4 percent by weight Sn, 0.1-4 percent by weight Zn, 0.1-4 percent by weight Pb, and 5.0 to 10 percent by weight Al, the balance being essenlmpact Value (Kg-m/cm") Note: the chemical composition of the alloy of Example 16-1 is 90.9% by weight of Cu. 0.9% by weight of Sn. 2.17: by weight of Zn. 0.87: by weight of Pb. 3.9% by weight of A1, 1.1% by weight of Fe and 0.3% by weight of impurities.

Table 22 illustrates the result of the charpy impact test made on U-notched test pieces of the alloy of Example 16-1.

The alloy of Example 16- exhibits a high impact value at each temperature stage. More specifically, the impact value of Example 16-1 is about 300 percent of those of the alloy of Example 16-2, and is about 200 tially copper.

2. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.14 percent by weight Sn, 0.1 4 percent by weight Zn, 0.1-4 percent by weight Pb, and 8.0 to 10 percent by weight Al, "the balance being essentially copper.

percent of the .115 AlBC 1 alloy, respectively. 3. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting EXAMPLE 17 essentially of 0.1 4 percent by weight Sn, 0.1-4 per- Table 23 Relative Alloy Chemical Composition (Z by weight) Value of Cu Sn Zn Pb Ni Al Others Machinability alloy of 91.5 l 2 0.5 0 4 1(Fe) Example 1'7-1 alloy of 85.5 1.5 1.5 3.5 l 7 Example 17-2 115 AlBC 1 86.3 0.3 9.1 3.5(Fe) 22 alloy free-cutting 61.5 35.5 3 brass rod 27 cent by weight Zn, 0.1 4 percent by weight Pb, 5.0 to 10 percent by weight Al and from 0.1 to 5.0 percent by weight Fe, the balance being essentially copper.

4. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 4 percent by weight Sn, 0.1 4 percent by weight Zn, 0.1 4 percent by weight Pb, 5.0 to l percent by weight Al, and at least one element selected from the group consisting of Ni in an amount up to percent by weight, Mn in an amount up to 3 percent by weight, and Be in an amount up to 0.1 percent by weight, the balance being essentially copper.

5. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 4 percent by weight Sn, 0.1 4 percent by weight Zn, 0.l4 percent by weight pb, 5.0 to percent by weight Al, 0.1 to 5.0 percent by weight Fe, and at least one element selected from the group consisting of Ni in an amount up to 5 percent by weight, Mn in an amount of to 3 percent by weight, and Be in an amount up to 0.1 percent by weight, the balance being essentially copper.

6. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting 28 essentially of 0.1 4 percent by weight Sn, 0.1 4 percent by weight Zn, 0.1 4 percent by weight Pb, 8.0 to 10 percent by weight Al, and 0.1 to 5.0 percent by weight Fe, the balance being essentially copper.

7. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 4 percent by weight Sn, 0.1 4 percent by weight Zn, 0.1 4 percent by weight Pb, 8.0 to 10 percent by weight Al, and at least one element selected from the group consisting of Ni in an amount up to 5 percent by weight, Mn in an amount up to 3 percent by weight, and Be in an amount up to 0.1 percent by weight, the balance being essentially copper.

8. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 4 percent by weight Sn, 0.1 4 percent by weight Zn, 0.1 -4 percent by weight Pb, 8.0 to 10 percent by weight A1, 0.1 to 5.0 percent by weight Fe, and at least one element selected from the group consisting of Ni in an amount up to 5 percent by weight, Mn in an amount up to 3 percent by weight, and Be in an amount up to 0.1 percent by weight, the

balance being essentially copper. 

1. A HIGH STRENGTH COPPER BASE ALLOY POSSESSING EXCELLENT CORROSION RESISTANCE AND MACHINABILITY, CONSISTING ESSENTIALLY OF 0.1 - 4 PERCENT BY WEIGHT SN, 0.1-4 PERCENT BY WEIGHT ZN, 0.1-4 PERCENT BY WEIGHT PB, AND 5.0 TO 10 PERCENT BY WEIGHT AL, THE BALANCE BEING ESSENTIALLY COPPER.
 2. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1-4 percent by weight Sn, 0.1 - 4 percent by weight Zn, 0.1-4 percent by weight Pb, and 8.0 to 10 percent by weight Al, the balance being essentially copper.
 3. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 - 4 percent by weight Sn, 0.1-4 percent by weight Zn, 0.1-4 percent by weight Pb, 5.0 to 10 percent by weight Al and from 0.1 to 5.0 percent by weight Fe, the balance being essentially copper.
 4. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 - 4 percent by weight Sn, 0.1 - 4 percent by weight Zn, 0.1 -4 percent by weight Pb, 5.0 to 10 percent by weight Al, and at least one element selected from the group consisting of Ni in an amount up to 5 percent by weight, Mn in an amount up to 3 percent by weight, and Be in an amount up to 0.1 percent by weight, the balance being essentially copper.
 5. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 - 4 percent by weight Sn, 0.1 - 4 percent by weight Zn, 0.1-4 percent by weight pb, 5.0 to 10 percent by weight Al, 0.1 to 5.0 percent by weight Fe, and at least one element selected from the group consisting of Ni in an amount up to 5 percent by weight, Mn in an amount of to 3 percent by weight, and Be in an amount up to 0.1 percent by weight, the balance being essentially copper.
 6. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 - 4 percent by weight Sn, 0.1 - 4 percent by weight Zn, 0.1 -4 percent by weight Pb, 8.0 to 10 percent by weight Al, and 0.1 to 5.0 percent by weight Fe, the balance being essentially copper.
 7. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 - 4 percent by weight Sn, 0.1 - 4 percent by weight Zn, 0.1 -4 percent by weight Pb, 8.0 to 10 percent by weight Al, and at least one element selected from the group consisting of Ni in an amount up to 5 percent by weight, Mn in an amount up to 3 percent by weight, and Be in an amount up to 0.1 percent by weight, the balance being essentially copper.
 8. A high strength copper base alloy possessing excellent corrosion resistance and machinability, consisting essentially of 0.1 - 4 percent by weight Sn, 0.1 - 4 percent by weight Zn, 0.1 -4 percent by weight Pb, 8.0 to 10 percent by weight Al, 0.1 to 5.0 percent by weight Fe, and at least one element selected from the group consistIng of Ni in an amount up to 5 percent by weight, Mn in an amount up to 3 percent by weight, and Be in an amount up to 0.1 percent by weight, the balance being essentially copper. 